Assessment of urban ecosystem resilience using the efficiency of hybrid social-physical complex networks

TL;DR

This paper introduces a novel methodology to quantify urban resilience by modeling cities as hybrid social-physical networks and measuring their efficiency before and after catastrophic events, bridging engineering and ecosystem perspectives.

Contribution

It proposes a new hybrid network model and efficiency measures to assess urban resilience, incorporating social and physical components, and demonstrates its application through a case study of earthquake recovery in Italy.

Findings

Efficiency measures effectively quantify resilience changes.

Different reconstruction strategies vary in restoring network efficiency.

Hybrid network modeling captures social-physical interactions in urban resilience.

Abstract

One of the most important tasks of urban and hazard planning is to mitigate the damages and minimize the costs of the recovery process after catastrophic events. The rapidity and the efficiency of the recovery process are commonly referred to as resilience. Despite the problem of resilience quantification has received a lot of attention, a mathematical definition of the resilience of an urban community, which takes into account the social aspects of a urban environment, has not yet been identified. In this paper we provide and test a methodology for the assessment of urban resilience to catastrophic events which aims at bridging the gap between the engineering and the ecosystem approaches to resilience. We propose to model a urban system by means of different hybrid social-physical complex networks, obtained by enriching the urban street network with additional information about the social and physical constituents of a city, namely citizens, residential buildings and services. Then, we introduce a class of efficiency measures on these hybrid networks, inspired by the definition of global efficiency given in complex network theory, and we show that these measures can be effectively used to quantify the resilience of a urban system, by comparing their respective values before and after a catastrophic event and during the reconstruction process. As a case study, we consider simulated earthquakes in the city of Acerra, Italy, and we use these efficiency measures to compare the ability of different reconstruction strategies in restoring the original performance of the urban system.